If you want to change the owner of a room, the usual practice is to reach out to the room owner and ask them to make the change on your behalf. However, if there is only one owner who is unavailable to make the desired changes, Symphony admins can use REST APIs to make this change.
Symphony REST APIs can be used by an Administrator to either promote an existing member in the room to room owner or add a new member into that room conversation as an owner to make the desired change.
Note: Speak with your internal IT team first before making any changes using the REST API
Further information can be found here.